[postgis-users] regularly spaced address markers on alternating side of road

Dan Jacobson jidanni at jidanni.org
Thu Jun 30 18:02:15 PDT 2016


Thanks. I did
$ qgis numbers/chain_number.qgs
and indeed saw your line with the four digit numbers on it.

Actually I think I should avoid doing my project by hand via
mouseclicks (Qgis), and instead learn PostGIS and write "batch job" SQL script
SELECT points WHERE each point is at 25 meter increments from the start
of road. Then print label on alternating side of road etc.
Maybe I can accomplish the whole thing without a GUI.

I'll send this to both lists.

>>>>> "FMRdM" == Fernando M Roxo da Motta <petro at roxo.org> writes:

FMRdM> On Wed, 29 Jun 2016 14:38:52 +0800, Dan Jacobson <jidanni at jidanni.org>
FMRdM> wrote:

FMRdM>   Hello,

FMRdM>   I am sending attached a ZIP with a simple project with a line and a
FMRdM> point layer result of a chainage each 25 meters.

FMRdM>   I don't know if I got your problem exactly, but in this project I
FMRdM> used the chainage result to label the layer.

FMRdM>   I was not able to make the layer going on alternate sides of the line
FMRdM> as desired, but perhaps this can be a start.

FMRdM>   In order to put the label on the point I choose in placement the
FMRdM> option "offset from point" and made the offset zero.

FMRdM>   It is possible to play with the marker (ex. make it have transparent
FMRdM> fill and border in order to make it invisible).

FMRdM>   I think it will make it look like the map you pointed in the link
FMRdM> bellow.

> Thanks. The idea is every 25 meters there should be a (proposed) house
> number (location) on the left, then one on the right, left, etc.
> Making for a total of 20 + 20 = 40 per kilometer.
> Sort of like what I did with GRASS years ago
> http://jidanni.org/geo/house_numbering/mountain.html
> but clearer via using two sides of the roads... but just putting them
> all down the middle would be OK too. Yes, it would be good to avoid
> depending on plugins.
> In fact just a bunch of dots along the center of the road would be
> fine, which then I suppose I could hack the .qgs file to add labels
> to with a perl script which I thankfully know how to write. I'll just
> remind the government workers to remember odd goes on the left, etc.


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